PDF export: Add warning that feature is beta

CHANGELOG.md

@@ -23,7 +23,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Unit-specific comments. [#761](https://github.com/geli-lms/geli/issues/761)
 - Simple E2E test for login. [#795](https://github.com/geli-lms/geli/pull/795)
 - Checkboxes for accepting our terms of use and privacy declarations while registering. [#778](https://github.com/geli-lms/geli/issues/778)
-- PDF course content download functionality. [#720](https://github.com/geli-lms/geli/pull/720)
+- PDF course content download functionality. [#720](https://github.com/geli-lms/geli/pull/720), [#923](https://github.com/geli-lms/geli/pull/923)
 - User data deletion functionality for EU-GDPR compliance. [#775](https://github.com/geli-lms/geli/issues/775)
 - Personal data export functionality for EU-GDPR compliance. [#805](https://github.com/geli-lms/geli/issues/805)
 - Guided dialog for adding a whitelist. [#727](https://github.com/geli-lms/geli/issues/727) [#509](https://github.com/geli-lms/geli/issues/509)

app/webFrontend/src/app/course/course-detail/course-detail.component.ts

@@ -56,7 +56,7 @@ export class CourseDetailComponent implements OnInit, OnDestroy {
         this.tabs = [{path: 'overview', label: t['common.content'], img: 'school'},
           {path: 'fileview', label: t['common.documents'], img: 'insert_drive_file'},
           {path: 'videoview', label: t['common.videos'], img: 'video_library'},
-          {path: 'download', label: t['common.download'], img: 'get_app'}];
+          {path: 'download', label: t['common.download'] + ' (Beta)', img: 'get_app'}];
       });
   }
 

app/webFrontend/src/app/course/course-detail/download-course-dialog/download-course-dialog.component.html

@@ -1,5 +1,12 @@
 <div *ngIf="this.checkForEmptyLectures()">
   <mat-card class="dl-card">
+    <mat-card-content>
+      <p class="beta-warning">
+        Heads up! The download feature is still in development.
+        We assume that for most lectures the export works quite well but there are some corner cases where the export might not work as you expect.
+        If you find a mistake please report it back to <a href="https://github.com/geli-lms/geli/issues" target="_blank">https://github.com/geli-lms/geli/issues</a>
+      </p>
+    </mat-card-content>
     <mat-card-content>
       <ng-container *ngIf="!this.checkForEmptyLectures()">{{'common.text.downloadNoFiles' | translate}}</ng-container>
       <mat-list>

app/webFrontend/src/app/course/course-detail/download-course-dialog/download-course-dialog.component.scss

@@ -49,3 +49,8 @@
 .radio-buttons .radio-button:nth-child(n+2){
   margin-left: 20px;
 }
+
+.beta-warning {
+  color: red;
+  font-weight: bolder;
+}